Long-term Vegetation Changes in Ponderosa Pine-Bunchgrass Ecosystems

Cooperating Agencies:

• U.S.D.A. Forest Service

Location:

Arizona and New Mexico

Date Initiated:

The original plots were established as early as 1909. Our re-measurements began in 1997.

Description:

Two types of plots were established in the early 1900s to study forest dynamics: stand-scale plots focused on overstory dynamics, and small-scale plots focused on herbaceous understory dynamics. First, the stand-scale (i.e., several-acre) plots were established in which all trees were mapped and measured in 5 year increments (Woolsey 1912; Pearson 1923, 1933, 1942). Both T.S. Woolsey, Jr., Assistant District Forester and Chief of the Office of Silviculture, District 3 (Southwestern District, now Southwest Region 3), USFS; and G. A. Pearson, Director, Fort Valley Forest Experiment Station (Flagstaff, AZ), USFS, were instrumental in the establishment and measurement of these overstory plots, but we call them the “Woolsey plots” because it was Woolsey’s idea. These plots were established in Arizona and New Mexico across a broad range of soil parent material.

Second, small-scale (i.e., 1 m2) quadrats were established to evaluate the effects of grazing on bunchgrass plant communities. R.R. Hill, District 3 (now USFS Region 3) Chief of Grazing Studies, established most of the original quadrats; hence, we call them the “Hill plots” (Talbot and Hill 1923, Arnold 1950). These herbaceous understory plots were located within a 700 km2 area around Flagstaff, Arizona across a broad soil gradient (see map). These plots also include quadrats that were established by G.A. Pearson and C. K. Cooperrider, Range Scientist, Fort Valley Experimental Station, on the Wild Bill Experimental Range near Kendrick Mountain (Cooperrider 1938, 1939).

Objectives related to the "Woolsey plots":

• Determine changes in forest composition and structure (density, size, and age) on permanent plots between the plot establishment date (1909-1914) and contemporary conditions.
• Reconstruct forest structure for each plot at its establishment date (1909-1914) using dendro-chronological techniques. Compare the reconstructed (modeled) and the historical (actual) forest structure for each plot to determine the precision, errors, and limitations of our reconstruction techniques and models.
• Use the Forest Vegetation Simulator (FVS) or other appropriate models to determine and link stand structural changes with functional changes (tree biomass, carbon and nitrogen storage, herbaceous production, fire susceptibility) on these plots from the time of fire regime disruption (ca. 1870-1890) and initial plot establishment (1909-1914) until the present. Also, project future conditions based on alternative management scenarios.

Objectives related to the "Hill plots":

• Quantify changes in plant species richness, plant basal cover, and community composition between plot establishment (ca. 1912) and current conditions and relate these to changes in overstory densities and soil properties.
• Determine the functional consequences of long-term vegetation changes by examining the relationship between internal nitrogen cycling and plant diversity and composition.

For More Information:

• Margaret M. Moore, , Professor, Northern Arizona University
• Daniel Laughlin, , PhD student, Northern Arizona University
• Jonathan D. Bakker, Assistant Professor, University of Washington
• Andrew Sanchez-Meador, U.S. Forest Service, Fort Collins, CO
• Susan D. Olberding, Archivist and Historian, USFS Rocky Mountain Research Station, Flagstaff, AZ

Historical Publications:

• Arnold, J.E. 1950. Changes in ponderosa pine bunchgrass ranges in northern Arizona resulting from pine regeneration and grazing. Journal of Forestry 48:118-126.
• Cooperrider, C.K. 1938. Recovery processes of ponderosa pine reproduction following injury to young annual growth. Plant Physiology 13:5-27.
• Cooperrider, C.K. 1939. Grazing and western timber reproduction. Proceedings of the Range Research Seminar, U.S. Forest Service, pp. 375-380.
• Hill, R. R. 1920. Charting quadrats with a pantograph. Ecology 1(4):270-273.
• Pearson, G.A. 1923. Natural reproduction of western yellow pine in the Southwest. USDA, For. Serv. Bull. 105. Washington, D.C. 143 p.
• Pearson, G. A. 1933. A twenty-year record of changes in an Arizona pine forest. Ecology 4:272-285.
• Pearson, G. A. 1942. Herbaceous vegetation a factor in natural regeneration of ponderosa pine in the southwest. Ecological Monographs 12:315-338.
• Talbot, M. W., and R. R. Hill. 1923. Progress report on the range study plots on the Coconino National Forest comprising a description of project and digest of data. Unpublished document in Fort Valley Archives, Flagstaff, AZ. 32 p.
• Woolsey, T.S., Jr. 1912. Permanent sample plots. Forest Quarterly 10:38-44.

Contemporary Publications:

• Bakker, J.D. 2005. A new, proportional method for reconstructing historical tree diameters. Canadian Journal of Forest Research. 35:2515-2520.M/li>
• Bakker, J.D. 2005. Long-term vegetation dynamics in ponderosa pine forests. Ph.D. Dissertation, Northern Arizona University, Flagstaff, Arizona. 164 p.
• Bakker, J.D., and M.M. Moore. 2007. Controls on vegetation structure in southwestern ponderosa pine forests, 1941 and 2004. Ecology 88:2305-2319.
• Bell, D. M., P. F. Parysow, and M. M. Moore. In press. Assessing the representativeness of the oldest permanent inventory plots in northern Arizona ponderosa pine forests. Restoration Ecology.
• Laughlin, D.C., J.D. Bakker, M.L. Daniels, M.M. Moore, C.A. Casey, J.D. Springer. In press. Restoring plant species diversity and community composition in a ponderosa pine-bunchgrass ecosystem. Plant Ecology.
• Moore, M.M., D.W. Huffman, P.Z. Fulé, W.W. Covington, and J.E. Crouse. 2004. Comparison of historical and contemporary forest structure and composition on permanent plots in southwestern ponderosa pine forests. Forest Science 50:162-176.
• Sánchez Meador, A.J., P. F. Parysow, and M. M. Moore. In review. Historical stem-mapped permanent plots increase precision of reconstructed reference data in ponderosa pine forests of northern Arizona. Restoration Ecology.
• Sánchez Meador, A.J. 2006. Modeling spatial and temporal changes of ponderosa pine forests in northern Arizona since Euro-American settlement. Ph.D. Dissertation, Northern Arizona University, Flagstaff, Arizona. 154 p.
• Sánchez Meador, A.J., M.M. Moore, J.D. Bakker, and P.F. Parysow. Accepted. Short- and long-term effects of selective harvesting on spatial pattern and stand development in a ponderosa pine forest. Journal of Vegetation Science.
• Sánchez Meador, A.J., P. F. Parysow, and M. M. Moore. Accepted. Historical stem-mapped permanent plots increase precision of reconstructed reference conditions in ponderosa pine forests of northern Arizona. Restoration Ecology.